Multi-model fusion for assessing the risk of inrush of limestone karst water through mine floor

Inrush of limestone karst water through mine floor occurs frequently in the Carboniferous-Permian coalfield in northern China. How to accurately evaluate the risk of inrush of limestone karst water through mine floor has guiding significance for preventing and controlling water disaster accidents in coal mines and realizing the safe mining of coal seams above confined water bodies. The unascertained measurement evaluation and set pair analysis method were pro-posed to evaluate water inrushes using eight indices:aquifer thickness,unit water inflow,permeability of aquifers,water pressure,fault influencing factors,aquiclude thickness,aquiclude lithologic assemblage characteristics and destroyed floor depth. Ordered binary comparison quantization method and interval number fuzzy decision matrix of EA-TOPSIS ordering were used to obtain weights for these eight factors. Conflicting evidence theory was then applied to couple these weights calculated by ordered binary comparison quantization and EA-TOPSIS ordering,ensuring the effective evaluation of the relative importance of each indicator for the dynamic model. Ultimately,the unascertained measure-ment evaluation and set pair analysis method were utilized to evaluate the risk of limestone karst water inrush from coal seam floor. Based on the type of index value,the state classification was carried out through quantitative analysis,and single index measure functions,including linear and non-linear patterns,were constructed. Then,eight indicator val-ues,collected at 30 monitoring sites in Xinwen coalfield for evaluating the risk of water inrush from coal seam floor, were substituted into the measure functions to determine the multi-index comprehensive measurement matrix. Credible degree recognition criterion was then introduced to determine the risk level of the sample data Xi . Furthermore,the general situation of risk of water inrush from coal seam floor during coal seam mining in Xinwen coalfield was presen-ted by means of set pair potential analysis. The research shows that the evaluation results are consistent with the actual situation of the mine. On this basis,according to a large number of water inrush cases collected in north China-type coal mines,taking 15 typical cases as examples,the established model was applied to the risk assessment of floor water inrush for the whole north China-type coal mines. By comparing with the actual water inrush data,it can be found that the hazard degree of mine water inrush determined by the model is consistent with the actual situation,which indicates that the model has certain suitability for evaluating the risk of karst water inrush from floor limestone in the whole north China-type coalfield.